/*
 * @(#)CharToByteDBCS_ASCII.java	1.11 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation. 
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt). 
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA 
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions. 
 *
 */
package sun.io;

public abstract class CharToByteDBCS_ASCII extends CharToByteConverter {
    private char highHalfZoneCode;
    private byte[] outputByte = new byte[2];
    protected short index1[];
    protected String index2;
    protected String index2a;
    protected int   mask1;
    protected int   mask2;
    protected int   shift;
    /**
     * flush out any residual data and reset the buffer state
     */
    public int flush(byte[] output, int outStart, int outEnd)
        throws MalformedInputException, ConversionBufferFullException {
        if (highHalfZoneCode != 0) {
            reset();
            badInputLength = 0;
            throw new MalformedInputException();
        }
        reset();
        return 0;
    }

    /**
     * Character conversion
     */
    public int convert(char[] input, int inOff, int inEnd,
        byte[] output, int outOff, int outEnd)
        throws UnknownCharacterException, MalformedInputException,
            ConversionBufferFullException {
        char    inputChar;
        int     inputSize;
        byteOff = outOff;
        charOff = inOff;
        while (charOff < inEnd) {
            int   index;
            int   theBytes;
            int   spaceNeeded;
            if (highHalfZoneCode == 0) {
                inputChar = input[charOff];
                inputSize = 1;
            } else {
                inputChar = highHalfZoneCode;
                inputSize = 0;
                highHalfZoneCode = 0;
            }
            // Is this a high surrogate?
            if (inputChar >= '\ud800' && inputChar <= '\udbff') {
                // Is this the last character of the input?
                if (charOff + inputSize >= inEnd) {
                    highHalfZoneCode = inputChar;
                    charOff += inputSize;
                    break;
                }
                // Is there a low surrogate following?
                inputChar = input[charOff + inputSize];
                if (inputChar >= '\udc00' && inputChar <= '\udfff') {
                    // We have a valid surrogate pair.  Too bad we don't do
                    // surrogates.  Is substitution enabled?
                    if (subMode) {
                        if (subBytes.length == 1) {
                            outputByte[0] = 0x00;
                            outputByte[1] = subBytes[0];
                        } else {
                            outputByte[0] = subBytes[0];
                            outputByte[1] = subBytes[1];
                        }
                        inputSize++;
                    } else {
                        badInputLength = 2;
                        throw new UnknownCharacterException();
                    }
                } else {
                    // We have a malformed surrogate pair
                    badInputLength = 1;
                    throw new MalformedInputException();
                }
            } // Is this an unaccompanied low surrogate?
            else
            if (inputChar >= '\uDC00' && inputChar <= '\uDFFF') {
                badInputLength = 1;
                throw new MalformedInputException();
            } else {
                // We have a valid character, get the bytes for it
                index = index1[((inputChar & mask1) >> shift)] + (inputChar & mask2);
                if (index < 15000)
                    theBytes = (int) (index2.charAt(index));
                else
                    theBytes = (int) (index2a.charAt(index - 15000));
                outputByte[0] = (byte) ((theBytes & 0x0000ff00) >> 8);
                outputByte[1] = (byte) (theBytes & 0x000000ff);
            }
            // if there was no mapping - look for substitution characters
            if (outputByte[0] == 0x00 && outputByte[1] == 0x00
                && inputChar != '\u0000') {
                if (subMode) {
                    if (subBytes.length == 1) {
                        outputByte[0] = 0x00;
                        outputByte[1] = subBytes[0];
                    } else {
                        outputByte[0] = subBytes[0];
                        outputByte[1] = subBytes[1];
                    }
                } else {
                    badInputLength = 1;
                    throw new UnknownCharacterException();
                }
            }
            if (outputByte[0] == 0x00)
                spaceNeeded = 1;
            else
                spaceNeeded = 2;
            if (byteOff + spaceNeeded > outEnd)
                throw new ConversionBufferFullException();
            if (spaceNeeded == 1)
                output[byteOff++] = outputByte[1];
            else {
                output[byteOff++] = outputByte[0];
                output[byteOff++] = outputByte[1];
            }
            charOff += inputSize;
        }
        return byteOff - outOff;
    }

    /**
     * Resets converter to its initial state.
     */
    public void reset() {
        charOff = byteOff = 0;
        highHalfZoneCode = 0;
    }

    /**
     * Returns the maximum number of bytes needed to convert a char.
     */
    public int getMaxBytesPerChar() {
        return 2;
    }

    /**
     * Returns true if the given character can be converted to the
     * target character encoding.
     */
    public boolean canConvert(char ch) {
        int  index;
        int  theBytes;
        index = index1[((ch & mask1) >> shift)] + (ch & mask2);
        if (index < 15000)
            theBytes = (int) (index2.charAt(index));
        else
            theBytes = (int) (index2a.charAt(index - 15000));
        if (theBytes != 0)
            return (true);
            // only return true if input char was unicode null - all others are
            //     undefined
        return (ch == '\u0000');
    }
}
